Macos – How to remove the EFI Partition on the USB using Mac OS X 10.11

macmacospartitioningps4usb

I need to remove the EFI partition on my USB because when trying to copy files from my PS4, the PS4 chooses this partition and ultimately runs out of space, instead of using the much larger space.

The EFI is about 200MB big and the USB storage is 16GB, apparently the only way to get the PS4 to write onto the large partition is to get rid of the EFI Partition.

Please help.

Patrick

Best Answer

Apple automatically and transparently creates an EFI partition on any GPT formatted disk (which is the default format). To get rid of it, you must reformat the flash drive with the MBR partition scheme.

In Disk Utility, choose the flash drive itself (not the volume under it) and choose Erase from the toolbar. In the window that comes up, make sure you have MS-DOS (FAT) selected as the format type (not shown in the screenshot below) and Master Boot Record selected as the scheme type.

NOTE: Make sure you select MS-DOS (FAT) as the format type. I grabbed and posted the screenshot before I realized I had the wrong format showing.

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Linux – How to remove iso 9660 from USB

Okay, it turns out that in this case something (possibly when I wrote the iso-9660 file system to the drive) has triggered some form of internal write protection on the drive. There are no external write protection / hold switches, but yet this is the output in dmesg when I run

dd if=/dev/zero of=/dev/sdb

as root:

sd 9:0:0:0: [sdb] Add. Sense: Write protected
end_request: I/O error, dev sdb, sector 4028744
sd 9:0:0:0: [sdb] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE,SUGGEST_OK
sd 9:0:0:0: [sdb] Sense Key : Data Protect [current] 
Info fld=0x0

Note the comments in there about protection! However, when I plug the device in, I get,

scsi 10:0:0:0: Direct-Access     FLASH    Drive  AU_USB20  8.07 PQ: 0 ANSI: 2
sd 10:0:0:0: [sdb] 4069376 512-byte hardware sectors (2084 MB)
sd 10:0:0:0: [sdb] Write Protect is off
sd 10:0:0:0: [sdb] Mode Sense: 03 00 00 00
sd 10:0:0:0: [sdb] Assuming drive cache: write through
sd 10:0:0:0: [sdb] 4069376 512-byte hardware sectors (2084 MB)
sd 10:0:0:0: [sdb] Write Protect is off
sd 10:0:0:0: [sdb] Mode Sense: 03 00 00 00
sd 10:0:0:0: [sdb] Assuming drive cache: write through

Note that this message says that the device is not write protected! So unfortunately, it looks like the disk has had it (i.e kaput).

Windows detected that the EFI system partition was formatted as NTFS

My current guess is that Windows searches all partitions on all fixed disks to find one that looks like an EFI System Partition, ignoring the partition type GUID. (This is probably for auto-repair reasons, since a wrong partition type GUID wouldn't actually prevent UEFI from booting from that partition, but I'm guessing Windows wants to correct it anyway.)

As a result it's probably misdetecting its own "installer" partition as the EFI System Partition due to it having an \EFI directory.

Possible workarounds:

Rename the \EFI directory on the NTFS partition to something like \NotEFI. You should still be able to start the bootloader, either through rEFInd or through the EFI Shell.
Delete (or rename) the \EFI directory from the NTFS partition as soon as the Windows installer has finished booting, by using the ShiftF10 terminal window. This should prevent the installer from picking it up as an EFI System Partition.
Boot the installer from a small USB stick, and place only the Install.wim file on the temporary NTFS partition (at the root of the filesystem). This should be supported for the last few Win10 releases, according to WinPE documentation.
Instead of using the standard installer, open the Shift+F10 terminal window and manually install Windows using dism /apply-image and bcdboot.

Best Answer

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Linux – How to remove iso 9660 from USB

Windows detected that the EFI system partition was formatted as NTFS

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